Lee de forest



No. 750,181. PATENTED JAN..19,.19'04 L. DE FOREST &-W. G. CLARK, DEVICEFOR CLEARING ICE FROM ANTENNAE.

APPLICATION FILED JUNE 17, 1903.

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UNITED STATES Patented January 19,1904.

PATENT ()FFICE.

LEE DE FOREST, OF NEW YORK, N. Y., AND WALTER G. CLARK OF I SEATTLE,WASHINGTON.

DEVICE FOR CLEARING ICE FROM ANTENN/E.

srncrmcn'rronforming part of Letters j tent No. 750,181, dated January19, 1904.

Application filed June 17, 190a To all w/tom it may concern.-

Be it known that we, LEE DE FOREST, a resident of the city, county, andState of New York, and WALTER G. CLARK, a resident of Seattle, Kingcounty, Washington, citizens of, the United States, have inventedcertain new and useful Improvements in Devices for Clearing Ice fromAntennae, of which the follow v posed conductors may be freed ofaccumulated 1 ice and the excessive and dangerous accumulation of icethereon be prevented.

The scope of our invention may be determined by an inspection of theclaims termiinvention.

nating this specification.

The drawings accompanying herewith illustrate a preferred form ofapparatus for carryv to melt any ice which may have accumulated ing outour invention.

Figure 1 illustrates diagrammatically and in a simple form a mechanismembodying our Fig. 2 in a similar manner represents an apparatusembodying our invention, the connection thereto of a complete sendingapparatus being illustrated.

In the erection of,wireless signaling apparatus in locations where theyare likely to be subjected to sleet-storms the protection there ofagainstthe weight of ice which is likely to accumulate-thereon .;becomesa serious problem, as these conductors are of considerable length. Inconsidering this problem we have devised an apparatus by means of whicha current may be sent through the antennae or other arranged in two ormore groups, as is shown Serial No. 161,89 (Ncmodeh) in Fig. 1, or areturn-conductor corresponding with one group of antennae is supplied,so that the conductors may be connectedin series, so as to produce acomplete circuit. The lower ends of the gro ups of antennae are arrangedto be connected withop'posite poles of a mechanism by which a largecurrent of low voltage may be produced. ,The most convenient means forproducing such a current and the means herein shown consists of astep-down transformer. The primary T of the transformer is connected'with a source of electromotive force, such source, being shown asconsisting of the alternating generator G. Terminals of the secondary ofthis transformer are connected with the respective group of antennae, so

that when current is passed through the transformer a current of largeamperage, but small voltage, will be passed ,throughthe antennae, whichwill result in sufficiently heating them thereon.

The apparatus'shown in Fig. 2 difiiers from that just described inillustrating means by which the step-down transformer may be connectedwith the generator employed in sending the signals when it is desired tomelt ice from the terminals and at other times may be disconnectedtherefrom. In this figure T T represent, respectively, the primary andsecondary of a step-up transformer, which is employed for producing theelectrical oscillations by the usual means, which include the sparkgap Sand key D. B represents a switch which is permanently connected w groupof antennae and is adapted to 0 either with the points 1 and 3, in whichtion the apparatus is in condition for sen a signal, 'or to bedisengaged from these p and to engage the point 2, in which posi thesecondary of the step-down transformer is connected with the antennae bysuch means. The generator which is employed for sending the signals maybe thus utilized for clearing the antennae of ice.

The apparatus herein illustrated and described is given simply as oneform of apparatus which may be employed. It is well known to us thatother forms of apparatus may be employed for securing the same result.WV e do not, therefore, wish to be understood as limiting ourselves tothis particular form of apparatus, but claim any apparatus which isincluded within the scope of the claims ter-- minating thisspecification.

Having thus described our invention, what we claim, and desire to secureby Letters Patent, is

1. In a wireless signaling apparatus, the combination with an antenna, agenerator of electromotive force of large amperage, and a conductorconnected with the upper end of the antenna, of means for including saidconductor and the antenna in a closed circuit with said generator.

2. In a wireless signaling apparatus, the combination with an antennaand a conductor connected with the upper end of said antenna, of agenerator of electromotive force, a stepdown transformer adapted to haveits primary connected with said generator, and means for connecting theantenna and the conductor connecting with its upper end in a closedcircuit with the secondary of said transformer.

3. In awireless signaling apparatus, in combination, a plurality ofantennae adapted to be connected to form a complete circuit, and

means for passing a heating-current therethrough.

4. In a wireless signaling apparatus, in combination, a plurality ofantennae adapted to be connected to form a complete circuit, a stepdowntransformer and means for connecting the secondary of said transformerin said antennae-circuit.

5. In a wireless signaling apparatus, in com bination, a plurality ofantennae electrically connected at their upper ends, and means forconnecting their lower ends with a source of electromotive force adaptedto heat the antennae.

6. In a wireless signaling apparatus, in combination, two elevatedsupports, an elevated conductor extending between said supports butinsulated therefrom, a plurality of antennae connected with saidconductor, and means for connecting the lower ends of said antennae withopposite poles of a source of electromotive force whereby the saidantennae may be heated.

7.. In a wireless signaling apparatus, in combination, two elevatedsupports, an elevated conductor extending between said supports butinsulated therefrom, a pluralityv of antennae connected with saidconductor, a source of electromotive force, a step-down transformerhaving its primary in the circuit of said source of electromotive forceand means for connecting the secondary of said transformer with thelower ends of different antennae.

In testimony whereof we have hereunto affixed our signatures each in thepresence of two Witnesses.

LEE DE FOREST. WALTER (,i. CLARK.

itnesses for Lee De Forest:

P. A. HALL, H. L. REYNOLDS.

Witnesses for Walter G. Clark:

C. A. KILBOURNE, JAMES H. KANE.

